Focus searching method, semiconductor detection method, detection equipment and storage medium

Abstract

The invention discloses a focus searching method, a semiconductor detection method, detection equipment and a storage medium, and belongs to the technical field of semiconductor detection. The method comprises the following steps: controlling an objective table carrying a reference object and an object to be measured to move relative to an objective lens in the vertical direction, so that the reference object carried on the objective table and the objective lens are sequentially located at a plurality of different height distances in the vertical direction; the objective table is provided with a first bearing area and a second bearing area. And at each height distance, controlling to shoot a reference object on the objective table to obtain a reference image of the reference object at each height distance. And determining a target height distance based on the reference images of the reference object at the plurality of different height distances, the target height distance being used for determining an initial height distance between the objective table or the object to be measured and the objective lens when the object to be measured is scanned. By introducing the reference object, the accuracy of the determined target height distance can be improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor detection technology, and in particular to a focusing method, a semiconductor detection method, a detection device and a storage medium. Background Art

[0002] When inspecting semiconductors, the optimal object plane position is easily affected by environmental factors, resulting in focal plane drift. If no correction is performed, the image quality may be reduced, affecting the accuracy and stability of defect detection. Therefore, in order to ensure that the image quality obtained during the film measurement process remains in the best state, it is necessary to accurately evaluate the optimal object distance of the current objective lens imaging before each film measurement. However, for the dark field detection system, it is often affected by the object structure during the focusing process. That is to say, when the dark field detection system images an object with a periodic structure, a series of clear periodic images will be formed during the focusing process, thereby interfering with the judgment of the optimal object distance. In addition, the surface pattern of the graphic wafer usually has unpredictable structural fluctuations. If the unknown pattern of the graphic wafer is used as the object plane for focusing, it will also cause the focus to deviate from the optimal imaging object distance. Summary of the invention

[0003] In view of the problems existing in the prior art, the present application provides a focus finding method, a semiconductor detection method, a detection device and a storage medium, which can improve the accuracy of the determined target height distance by introducing a reference object, thereby accurately finding the focus. The technical solution is as follows: In one aspect, a focus finding method is provided, the method comprising: Controlling the relative movement of the stage carrying the reference object and the object to be measured and the objective lens in the vertical direction, so that the reference object carried on the stage and the objective lens are at a plurality of different height distances in the vertical direction in sequence; wherein the stage has a first carrying area and a second carrying area, the first carrying area is used to carry the object to be measured, and the second carrying area is used to carry the reference object; At each height distance, controlling to shoot the reference object on the stage to obtain a reference image of the reference object at each height distance; Based on the reference images of the reference object at a plurality of different height distances, a target height distance is determined, and the target height distance is used to determine an initial height distance between the stage or the object to be measured and the objective lens when scanning the object to be measured.

[0004] Optionally, after determining the target height distance based on the reference images of the reference object at a plurality of different height distances, the method further comprises: Control the stage to move to a corresponding height in the vertical direction according to the target height distance, and obtain the height value of the upper surface of the reference object when the stage is at this height as the target height value, and the target height value is used to indicate the height value that the upper surface of the test area corresponding to the object to be tested needs to be at when it is in the initial scanning position.

[0005] Optionally, determining the target height distance based on the reference images of the reference object at a plurality of different height distances comprises: For each reference image in the plurality of reference images: determining a plurality of focus regions in the reference image; determining regional energy concentration values ​​corresponding to the plurality of focus regions respectively; and determining an image energy concentration value corresponding to the reference image based on the plurality of regional energy concentration values; The target height distance is determined based on the image energy concentration values ​​respectively corresponding to the multiple reference images and the height distances respectively corresponding to the multiple reference images.

[0006] Optionally, determining the image energy concentration value corresponding to the reference image based on the multiple regional energy concentration values ​​includes: An average value of the plurality of regional energy concentration values ​​is used as the image energy concentration value corresponding to the reference image.

[0007] Optionally, the determining the target height distance based on the image energy concentration values ​​respectively corresponding to the multiple reference images and the height distances respectively corresponding to the multiple reference images comprises: Obtaining a reference curve graph according to the plurality of image energy concentration values ​​and the height distances respectively corresponding to the plurality of reference images; The height distance corresponding to the maximum image energy concentration value in the reference curve graph is determined as the target height distance.

[0008] Optionally, determining the regional energy concentration values ​​respectively corresponding to the plurality of focus regions comprises: For each of the plurality of regions of interest: Determine a central pixel in the focus area, where the central pixel is a pixel with the largest grayscale value in the focus area; Taking the central pixel as the center, determining a first sub-region, a second sub-region and a third sub-region in the region of interest, wherein the first sub-region is located at the periphery of the central pixel, the second sub-region is located at the periphery of the first sub-region, and the third sub-region is other regions in the region of interest that are located at the periphery of the second sub-region; Based on the first sub-region, the second sub-region and the third sub-region, corresponding regional energy concentration values ​​are determined.

[0009] Optionally, the determining corresponding regional energy concentration values ​​based on the first sub-region, the second sub-region, and the third sub-region includes: determining an average noise based on pixels in the second sub-area and pixels in the third sub-area; Determine a plurality of grayscale pixels in the first sub-region, wherein the plurality of grayscale pixels include a first pixel in the first sub-region having a maximum grayscale value and at least one pixel whose grayscale value is successively smaller than the grayscale value of the first pixel; determining a first energy value based on the plurality of grayscale pixels and the average noise; determining a second energy value based on pixels in the second sub-region and the average noise; The regional energy concentration value is determined based on the first energy value and the second energy value.

[0010] Optionally, determining the first energy value based on the plurality of grayscale pixels and the average noise includes: Deducting the average noise from each grayscale pixel of the plurality of grayscale pixels to obtain a plurality of grayscale pixels after deducting the average noise; The grayscale values ​​of the plurality of grayscale pixels after deducting the average noise are added together to obtain the first energy value.

[0011] Optionally, determining the second energy value based on the pixels in the second sub-region and the average noise includes: Deducting the average noise from each pixel in the second sub-area to obtain a plurality of pixels after deducting the average noise; The grayscale values ​​of the plurality of pixels after deducting the average noise are added together to obtain the second energy value.

[0012] Optionally, determining the regional energy concentration value based on the first energy value and the second energy value includes: The ratio of the first energy value to the second energy value is determined as the regional energy concentration value.

[0013] Optionally, the reference object is a standard part, the surface of the standard part has a plurality of circular pits with the same diameter and the same recessed distance, and the plurality of circular pits are arranged in a rectangular shape; or, The reference object is another object to be tested that is different from the object to be tested located in the first carrying area.

[0014] Optionally, bottom surfaces of the first bearing area and the second bearing area are in the same horizontal plane.

[0015] On the other hand, a focus finding method is provided, the method comprising: Controlling the relative movement of the stage carrying the reference object and the objective lens in the vertical direction, so that the reference object carried on the stage and the objective lens are at a plurality of different height distances in the vertical direction in sequence; At each height distance, controlling the reference object on the stage to be photographed to obtain a reference image of the reference object at each height distance; Based on the reference images of the reference object at multiple different height distances, a target height distance is determined. The target height distance is used to determine the initial height distance between the stage or the object to be measured and the objective lens when scanning the object to be measured when the object to be measured is carried on the stage.

[0016] Optionally, the stage has a first bearing area, and the first bearing area is used to bear the object to be measured; the reference object is the object to be measured.

[0017] Optionally, determining the target height distance based on the reference images of the reference object at a plurality of different height distances comprises: For each reference image in the plurality of reference images: determining a plurality of focus regions in the reference image; determining regional energy concentration values ​​corresponding to the plurality of focus regions respectively; and determining an image energy concentration value corresponding to the reference image based on the plurality of regional energy concentration values; The target height distance is determined based on the image energy concentration values ​​respectively corresponding to the multiple reference images and the height distances respectively corresponding to the multiple reference images.

[0018] In another aspect, a semiconductor detection method is provided, the method comprising: Controlling the relative movement of a stage carrying an object to be tested and an objective lens along a scanning direction to sequentially reach a plurality of scanning positions, wherein the object to be tested is a semiconductor sample; wherein the relative movement of the stage and the objective lens in a vertical direction is controlled according to a target height distance so that the upper surface of the test area corresponding to the object to be tested at an initial scanning position is at a desired height, and the target height distance is determined based on the focus finding method described above; During the scanning process, the upper surface of the test area corresponding to the test object at the initial scanning position of the test object is at a desired height as the follow focus zero point to control the full follow focus of the test object, and after automatic focusing at each scanning position, control the imaging of the test object to obtain the test image of the test area corresponding to the current scanning position of the test object; The area to be tested is detected based on the image to be tested.

[0019] In another aspect, a detection device is provided, comprising: The stage has a first carrying area, and the first carrying area is used to carry the object to be tested; An imaging optical path component, comprising a detection sensor and an objective lens; the imaging optical path component is used to perform optical imaging of the object to be detected and the reference object on the stage through the objective lens, and transmit the optical signal obtained by imaging to the detection sensor, and the detection sensor is used to convert the optical signal into an electrical signal, so as to obtain a detection image of the object to be detected and / or a reference image of the reference object; A driving assembly, used for driving the stage and the objective lens to move relative to each other; A processor is used to execute the method described in any embodiment of the present invention.

[0020] On the other hand, a computer-readable storage medium is provided, wherein a computer program is stored in the storage medium, and when the computer program is executed by a processor, the steps of the above-mentioned focusing method or semiconductor detection method are implemented.

[0021] On the other hand, a computer program product comprising instructions is provided. When the instructions are executed on a computer, the computer executes the steps of the above-mentioned focusing method or semiconductor detection method.

[0022] The technical solution provided by this application can at least bring the following beneficial effects: By introducing a reference object, and the reference object is located in the second bearing area of ​​the stage, by controlling the relative movement of the stage and the objective lens in the vertical direction, and controlling the reference object on the stage to be photographed at each height distance, a plurality of reference images can be obtained, and then, the target height distance is determined according to the reference images of the reference object at a plurality of different height distances. That is, the embodiment of the present application is based on the reference object for focusing, thereby avoiding the situation that it is difficult to find a fixed graphic feature as the object of focusing imaging due to the different graphic types corresponding to the various areas of the object to be tested, and improving the accuracy of focusing, thereby improving the imaging quality of the object to be tested in the subsequent process, and further improving the detection accuracy of the object to be tested; moreover, it can avoid the situation that when the object to be tested is directly focused, errors are generated due to the fluctuation of the graphic structure of the object to be tested and the Talbot effect.

[0023] In addition, a reference curve graph is determined based on the height distances corresponding to the multiple image energy concentration values ​​and the multiple reference images, so that in the subsequent process, the target height distance can be directly determined from the reference curve graph. Moreover, the average value of the multiple regional energy concentration values ​​is used as the image energy concentration value corresponding to the reference image, which can improve the accuracy of the determined target height distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1A schematic diagram of the structure of a detection device provided in an embodiment of the present application; Figure 2 A flow chart of a focus finding method provided in an embodiment of the present application; Figure 3 A schematic diagram of the structure of a stage provided in an embodiment of the present application; Figure 4 A schematic diagram of the structure of a standard component provided in an embodiment of the present application; Figure 5 A schematic diagram of a reference image provided in an embodiment of the present application; Figure 6 A schematic diagram of a region of interest provided in an embodiment of the present application; Figure 7 A schematic diagram of a reference curve graph provided in an embodiment of the present application; Figure 8 A flowchart of another focus finding method provided in an embodiment of the present application; Fig. 9 A flowchart of a semiconductor detection method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are for making the present application better understood. However, those skilled in the art can easily recognize that some features can be omitted in different situations, or can be replaced by other elements, materials, methods. In some cases, some operations related to the present application are not shown or described in the specification, this is to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0026] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0027] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0028] Before explaining in detail the focusing method, semiconductor detection method, detection equipment and storage medium provided in the present application, the application scenarios and implementation environment of the embodiments of the present application are first introduced.

[0029] In the detection system, environmental factors (such as temperature changes, mechanical vibrations, etc.) may affect the position of the optimal object plane. If no correction is performed, the image quality may be reduced, thereby affecting the accuracy and stability of the detection. In the related art, the autofocus solution mainly relies on image contrast analysis to determine the optimal object distance. However, in the dark field imaging system, due to the significant influence of the object structure, it is difficult to accurately judge the focal plane position, especially when coherent illumination imaging is performed on samples with periodic structures. The Talbot effect may occur, resulting in a series of clear periodic images, making it difficult to accurately judge the optimal object distance. In addition, the surface pattern of the object to be tested usually has unpredictable structural fluctuations. Directly focusing on its pattern may cause the focal plane to shift, affecting the imaging clarity and defect detection accuracy.

[0030] Based on this, the embodiment of the present application introduces a reference object, obtains the height distance of the optimal object distance by imaging the standard object, and inputs it into the automatic focus system as the initial focus height, so as to achieve dynamic adjustment during the whole film scanning process, and ensure that the imaging system can accurately and automatically follow and always maintain the optimal focus plane. It can effectively reduce the interference of environmental changes and sample structure on the focusing process, thereby improving the accuracy and stability of automatic focus, and improving the reliability and consistency of the detection results.

[0031] Please refer to Figure 1 , Figure 1 It is a structural schematic diagram of a detection device provided in an embodiment of the present application, wherein the detection device includes a stage 1, an imaging optical path component 2, a drive component 3 and a processor 4, wherein the imaging optical path component 2 includes a detection sensor 21 and an objective lens 22.

[0032] The stage 1 has a first carrying area 11, and the first carrying area 11 is used for carrying the object to be tested.

[0033] In some embodiments, the stage 1 is movable, and the movement of the stage 1 can drive the object to be tested thereon to move.

[0034] In some embodiments, the stage 1 can move along the scanning direction, thereby driving the carried object to be tested to move along the scanning direction, so that the detection device can scan the entire surface of the object to be tested.

[0035] In some embodiments, the scanning direction may be an X-axis direction, a Y-axis direction, or a plane direction defined by the X-axis and the Y-axis (eg, a horizontal direction or a horizontal plane direction).

[0036] In some embodiments, the stage 1 can move along the optical axis of the objective lens 22, thereby driving the carried object to be measured to move along the optical axis of the objective lens 22. For example, the optical axis of the objective lens 22 may be the Z axis direction (eg, vertical direction).

[0037] Therefore, in some embodiments, the stage 1 can move along the Z-axis direction (eg, vertical direction), thereby driving the carried object to be measured to move along the Z-axis direction (eg, vertical direction).

[0038] In addition, in some embodiments, in order to perform focus search through a reference object, that is, to determine the target height distance through a reference object, please refer to Figure 1 The stage 1 also has a second carrying area 12, and the second carrying area 12 is used to carry the reference object. Therefore, when the stage 1 moves, it can also drive the carried reference object to move to perform related steps.

[0039] It should be noted that the object to be tested in the embodiments of the present application may be a semiconductor product such as a wafer or a chip. Since there may be defects such as flaws on its surface, it is necessary to perform optical inspection on its surface in order to control the quality of the product.

[0040] The imaging optical path component 2 is used to perform optical imaging of the object to be tested and the reference object on the stage 1 through the objective lens 22, and transmit the optical signal obtained by imaging to the detection sensor 21. The detection sensor 21 is used to convert the optical signal into an electrical signal, so as to obtain a detection image of the object to be tested and / or a reference image of the reference object.

[0041] In some embodiments, the detection sensor 21 may be a TDI (Time Delayed and Integration) camera.

[0042] It should be noted that, in addition to the detection sensor 21 and the objective lens 22, the imaging optical path component 2 may also include other components, such as other optical devices arranged in the optical path between the detection sensor 21 and the objective lens 22, such as a collimating lens or even a filter, a spectrometer, etc.; in addition, the imaging optical path component 2 may also include a light source, and the illumination light emitted by the light source is projected onto the object to be tested carried by the stage 1 after passing through the objective lens 22, and the light formed by the surface reflection and scattering of the object to be tested is collected by the objective lens 22 and then incident on the detection sensor 21. The light source may be any one of LED (Light Emitting Diode), xenon lamp, mercury lamp, halogen lamp, laser lamp, laser plasma lamp, and laser-driven white light source lamp, so the illumination light may be white light, colored light or laser.

[0043] The driving component 3 is used to drive the relative movement of the stage 1 and the objective lens 22. The driving component 3 may drive the stage 1 to move while the objective lens 22 remains stationary, or the driving component 3 may drive the objective lens 22 to move while the stage 1 remains stationary, or the driving component 3 may drive the stage 1 to move and drive the objective lens 22 to move.

[0044] For example, the drive component 3 drives the stage 1 and the objective lens 22 to move relative to each other along the scanning direction. The drive component 3 may drive the stage 1 to move along the scanning direction while the objective lens 22 remains stationary, or the drive component 3 drives the objective lens 22 to move along the scanning direction while the stage 1 remains stationary. The drive component 3 may also drive the stage 1 to move and drive the objective lens 22 to move so as to achieve relative movement of the two along the scanning direction.

[0045] As another example, the drive component 3 drives the objective lens 22 to move relative to each other along the optical axis of the objective lens 22. The drive component 3 may drive the objective lens 22 to move along the optical axis while the objective lens 22 remains stationary. The drive component 3 may drive the objective lens 22 to move along the optical axis while the stage 1 remains stationary. The drive component 3 may also drive the stage 1 to move and drive the objective lens 22 to move so as to achieve relative movement of the two along the optical axis.

[0046] Therefore, the driving component 3 drives the objective lens 22 to move relative to each other along the Z-axis direction (for example, the vertical direction). The driving component 3 may drive the objective lens 22 to move along the Z-axis direction (for example, the vertical direction) while the objective lens 22 remains stationary, or the driving component 3 drives the objective lens 22 to move along the Z-axis direction (for example, the vertical direction) while the objective lens 22 remains stationary. The driving component 3 may also drive the stage 1 to move and drive the objective lens 22 to move so as to achieve relative movement of the two along the Z-axis direction (for example, the vertical direction).

[0047] In some embodiments, the driving component 3 can be implemented based on driving components such as piezoelectric, servo motor, DD motor, etc.

[0048] The processor 4 includes but is not limited to a central processing unit (CPU), a microcontroller unit (MCU), a field-programmable gate array (FPGA), a digital signal processing (DSP), and other devices for interpreting computer instructions and processing data in computer software.

[0049] In some embodiments, the processor 4 is capable of executing each computer application in the non-temporary computer-readable storage medium, thereby executing the corresponding steps and methods. For example, the processor 4 can be implemented by software, hardware, firmware or a combination thereof, and can use a circuit, a single or multiple application-specific integrated circuits (Application Specific Integrated Circuit, ASIC), a digital signal processor (Digital Signal Processor, DSP), a digital signal processing device (Digital Signal Processing Device, DSPD), a programmable logic device (Programmable Logic Device, PLD), a field programmable gate array (Field Programmable Gate Array, FPGA), a central processing unit (Central Processing Unit, CPU), a controller, a microcontroller, a microprocessor, at least one of which enables the processor 4 to execute some steps or all steps of the focus search method in various embodiments of the present application or any combination of the steps therein, or, so that the processor 4 can execute some steps or all steps of the semiconductor detection method in various embodiments of the present application or any combination of the steps therein.

[0050] Next, the focusing method provided in the embodiment of the present application is explained in detail.

[0051] Figure 2 is a flow chart of a focus finding method provided in an embodiment of the present application, which is applied to the processor in the above detection device. Figure 2 , the method comprises the following steps: Step 201: Control the relative movement of the stage carrying the reference object and the object to be measured and the objective lens in the vertical direction, so that the reference object and the objective lens carried on the stage are successively at a plurality of different height distances in the vertical direction; wherein the stage has a first carrying area and a second carrying area, the first carrying area is used to carry the object to be measured, and the second carrying area is used to carry the reference object.

[0052] When inspecting the object to be tested, it is difficult to find a fixed graphic feature as the object of focus imaging because the graphic types corresponding to various areas of the object to be tested may be different. Therefore, a second carrying area for carrying a reference object in addition to the first carrying area for carrying the object to be tested may be added to the stage to perform a subsequent focus-finding process.

[0053] In some embodiments, the stage carrying the reference object and the object to be measured can be controlled to move, the objective lens remains stationary, and the stage is moved in the horizontal direction, so that the reference object carried on the stage is located directly below the objective lens; thereafter, the stage can be controlled to move in the vertical direction, so that the reference object carried on the stage and the objective lens are at a plurality of different height distances in the vertical direction in sequence.

[0054] In addition, in some embodiments, the objective lens can be controlled to move, the stage remains stationary, and the objective lens is moved in the horizontal direction so that the objective lens is located directly above the reference object carried on the stage; thereafter, the objective lens can be controlled to move in the vertical direction so that the reference object carried on the stage and the objective lens are at a plurality of different height distances in the vertical direction in sequence.

[0055] In some embodiments, the first loading area and the second loading area of ​​the loading platform are as follows: Figure 3 As shown, from Figure 3 It can be seen that the first carrying area is used to carry the object to be measured, the second carrying area is used to carry the reference object, and the first carrying area is connected to the second carrying area. Therefore, the imaging object can be switched between the object to be measured and the reference object without moving the stage or the objective lens significantly.

[0056] In some embodiments, the reference object may be a standard part, the surface of which has multiple circular pits with the same diameter and the same recessed distance, and the multiple circular pits are arranged in a rectangular shape; alternatively, the reference object may also be another object to be tested that is different from the object to be tested located in the first supporting area.

[0057] As an example, the reference may be Figure 4 The standard parts shown are from Figure 4 It can be seen from the figure that the depression distances of the multiple circular pits in the standard part are all d.

[0058] It should be noted that the reference object may be a standard part, or may be another object to be tested that is different from the object to be tested in the first bearing area, which is not limited in this embodiment of the present application.

[0059] In some embodiments, the bottom surfaces of the first bearing area and the second bearing area are on the same horizontal plane, thereby ensuring that the object to be measured and the reference object are placed on the same horizontal plane.

[0060] Step 202: At each height distance, control the reference object on the stage to be photographed to obtain a reference image of the reference object at each height distance.

[0061] That is to say, each time after controlling the relative movement of the stage and the objective lens in the vertical direction, it is necessary to control the reference object on the stage to be photographed at the height distance; after the photographing at the height distance is completed, the height distance between the reference object and the objective lens in the vertical direction can be changed, and then the reference object on the stage can be controlled to be photographed again. Repeat the above steps to obtain a reference image of the reference object at each height distance, that is, multiple reference images can be obtained, and each of the multiple reference images corresponds to a different height distance.

[0062] Step 203: Determine a target height distance based on the reference images of the reference object at multiple different height distances. The target height distance is used to determine an initial height distance between the stage or the object to be measured and the objective lens when scanning the object to be measured.

[0063] After obtaining reference images of the reference object at multiple different height distances, the target height distance may be determined based on the multiple reference images.

[0064] In some embodiments, the bottom surfaces of the first bearing area and the second bearing area of ​​the stage are in the same horizontal plane, and the upper surface of the object to be measured and the upper surface of the reference object are also in the same horizontal plane. Therefore, the target height distance determined according to the reference image corresponding to the reference object can be used to determine the initial height distance between the stage and the objective lens when scanning the object to be measured.

[0065] In addition, in some embodiments, the upper surface of the object to be measured and the upper surface of the reference object may not be in the same horizontal plane because the bottom surfaces of the first bearing area and the second bearing area of ​​the stage are not in the same horizontal plane, or because the thickness of the object to be measured is different from the thickness of the reference object, so the target height distance determined according to the reference image corresponding to the reference object can be used to determine the initial height distance between the upper surface of the object to be measured and the objective lens when scanning the object to be measured. In other words, the target height distance determined according to the multiple reference images is the height distance between the upper surface of the reference object and the objective lens, so the initial height distance between the upper surface of the object to be measured and the objective lens must be equal to the target height distance.

[0066] In some embodiments, for each reference image among the multiple reference images: multiple regions of interest (i.e., ROIs) in the reference image can be determined, and then, regional energy concentration values ​​corresponding to the multiple regions of interest are determined, and based on the multiple regional energy concentration values, an image energy concentration value corresponding to the reference image is determined, and then, based on the image energy concentration values ​​corresponding to the multiple reference images and the height distances corresponding to the multiple reference images, the target height distance is determined.

[0067] That is to say, after acquiring the multiple reference images, it is necessary to determine the corresponding multiple focus areas for each reference image, and determine the corresponding regional energy concentration value for each focus area in the multiple focus areas, so as to obtain the multiple regional energy concentration values ​​corresponding to each reference image, and then determine the image energy concentration value corresponding to each reference image based on the multiple regional energy concentration values.

[0068] As an example, see Figure 5 , Figure 5 is a schematic diagram of a reference image provided in an embodiment of the present application. Figure 5 It can be seen that the reference image includes multiple regions, and a total of 9 regions in the dotted box are selected as the focus areas from the multiple regions. Afterwards, it is necessary to determine the regional energy concentration values ​​corresponding to these 9 regions, and 9 regional energy concentration values ​​can be obtained. Therefore, the image energy concentration value corresponding to the reference image can be determined based on these 9 regional energy concentration values.

[0069] It should be noted that the above description is based on the selection of 9 focus regions, or, in application, any more or fewer regions in the reference image may be selected as focus regions according to circumstances. The present application embodiment does not limit this.

[0070] In some embodiments, the regional energy concentration value corresponding to each of the multiple regions of interest may be determined according to the following steps (1)-(3); (1) Determine the central pixel in the focus area, which is the pixel with the largest grayscale value in the focus area.

[0071] That is, the pixel with the largest gray value in the focus area can be determined as the central pixel. For example, please refer to Figure 6 , Figure 6 is a schematic diagram of a region of interest provided in an embodiment of the present application, wherein the central pixel is Figure 6 The gray area A0 in the figure.

[0072] (2) With the central pixel as the center, determine the first sub-region, the second sub-region and the third sub-region in the target area. The first sub-region is located outside the central pixel, the second sub-region is located outside the first sub-region, and the third sub-region is other regions in the target area that are located outside the second sub-region.

[0073] As an example, see Figure 6 , the first sub-region is Figure 6 The white area A1 in the second sub-area is Figure 6 The shaded area A2 in the figure is the third sub-area. Figure 6 The black area A3 in the figure.

[0074] It should be noted that Figure 6 The area sizes of the first sub-area, the second sub-area and the third sub-area are only examples, and in actual application, the area sizes of the first sub-area, the second sub-area and the third sub-area can be changed according to the situation. The embodiment of the present application does not limit this.

[0075] (3) Based on the first sub-region, the second sub-region, and the third sub-region, determine corresponding regional energy concentration values.

[0076] In some embodiments, the corresponding regional energy concentration values ​​may be determined based on the first sub-region, the second sub-region, and the third sub-region according to the following steps ae; a. Based on the pixels in the second sub-area and the pixels in the third sub-area, determine the average noise.

[0077] Since the second sub-region and the second sub-region both include a plurality of pixels, it is necessary to calculate the noise value of each of the plurality of pixels. For example, the noise value of each pixel is the difference between the pixel in the noisy image and the pixel in the focus area, wherein the noisy image refers to an image in which pixel values ​​have unexpected random changes due to various interferences, and such images usually contain abnormal brightness or color fluctuations that are not derived from the original scene.

[0078] It should be noted that the above description is based on the determination of the noise of each pixel according to the difference between the noisy image and the region of interest. Alternatively, in an application, the noise of each pixel may also be determined by other methods.

[0079] It should be noted that after obtaining the noises corresponding to the multiple pixels in the second sub-region and the third sub-region, the multiple noises may be averaged, and the obtained average value may be determined as the average noise. Alternatively, the standard deviation or median of the multiple noises may be calculated to determine the average noise. This embodiment of the present application does not limit this.

[0080] b. Determine a plurality of grayscale pixels in the first sub-region, wherein the plurality of grayscale pixels include a first pixel in the first sub-region with a maximum grayscale value and at least one pixel whose grayscale value is successively smaller than the grayscale value of the first pixel.

[0081] That is to say, it is necessary to determine a plurality of pixels with the largest grayscale value in the first sub-region, that is, the plurality of grayscale pixels include the first pixel with the largest grayscale value in the first sub-region and at least one pixel whose grayscale value is successively smaller than the grayscale value of the first pixel. As an example, assuming that there are pixels P1, P2, P3, P4, P5 and P6 in the first sub-region, and pixel P1 is the pixel with the largest grayscale value in the first sub-region, and the grayscale values ​​of pixels P2, P3, P4, P5 and P6 decrease successively; if it is necessary to select 4 grayscale pixels, then pixels P1, P2, P3 and P4 can be determined as grayscale pixels.

[0082] c. Determine a first energy value based on the plurality of grayscale pixels and the average noise.

[0083] In some embodiments, average noise may be subtracted from each of the plurality of grayscale pixels to obtain a plurality of grayscale pixels after average noise subtraction, and then the grayscale values ​​of the plurality of grayscale pixels after average noise subtraction may be added to obtain a first energy value.

[0084] After determining the plurality of grayscale pixels and the average noise, it is necessary to deduct the average noise from each of the plurality of grayscale pixels to reduce the interference of the noise, thereby improving the accuracy of the determined regional energy concentration value. Then, for the plurality of grayscale pixels after deducting the average noise, the grayscale value of each grayscale pixel is determined to obtain the grayscale values ​​corresponding to the plurality of grayscale pixels after deducting the average noise, and then the plurality of grayscale values ​​are added to determine the first energy value.

[0085] d. Determine a second energy value based on the pixels in the second sub-region and the average noise.

[0086] In some embodiments, average noise may be deducted from each pixel in the second sub-region to obtain a plurality of pixels after average noise deduction, and then grayscale values ​​of the plurality of pixels after average noise deduction are added to obtain the second energy value.

[0087] After determining the average noise, the average noise can be deducted from each pixel in the second sub-region to reduce the interference of noise and improve the accuracy of the regional energy concentration value determined subsequently. Then, for all pixels in the second sub-region after deducting the average noise, the gray value of each pixel is determined to obtain the gray value of each pixel in the second sub-region, and then the multiple gray values ​​are added to determine the second energy value.

[0088] e. Determine a regional energy concentration value based on the first energy value and the second energy value.

[0089] In some embodiments, after the first energy value and the second energy value are obtained, the ratio of the first energy value to the second energy value may be determined as the regional energy concentration value.

[0090] It should be noted that the above description is based on determining the ratio of the first energy value to the second energy value as the regional energy concentration value, or in application, the regional energy concentration value may be determined in other ways. This embodiment of the application does not limit this.

[0091] For each region of interest, after determining the regional energy concentration value corresponding to each region of interest according to the above steps ae to obtain multiple regional energy concentration values, the average value of the multiple regional energy concentration values ​​can be used as the image energy concentration value corresponding to the corresponding reference image.

[0092] Continuing with the above description, since the image energy concentration value of each reference image in the multiple reference images is the average of the regional energy concentration values ​​corresponding to the multiple focus areas in the reference image, therefore, in the subsequent process, the target height distance is determined according to the image energy concentration values ​​corresponding to the multiple reference images respectively, which can improve the accuracy of the determined target height distance and perform more precise focusing, thereby providing imaging quality when detecting the object to be tested in the subsequent process.

[0093] In some embodiments, in order to quickly determine the target height distance and still be able to obtain the target height distance in subsequent processes, a reference curve graph can be obtained based on multiple image energy concentration values ​​and the height distances corresponding to multiple reference images; the height distance corresponding to the largest image energy concentration value in the reference curve graph is determined as the target height distance.

[0094] Based on the above description, it is known that the image energy concentration value corresponding to each reference image can be determined, thereby obtaining multiple image energy concentration values. Moreover, since the multiple reference images are obtained by photographing the reference object on the stage at different height distances, it can be known that each of the multiple reference images has a corresponding height distance and image energy concentration value. Therefore, the reference curve graph can be determined according to the image energy concentration values ​​and height distances corresponding to the multiple reference images.

[0095] After the reference curve graph is obtained, the point with the highest image energy concentration value in the reference curve graph corresponds to the highest imaging quality. Therefore, the height distance corresponding to the point with the highest image energy concentration value can be determined as the target height distance.

[0096] As an example, see Figure 7, Figure 7 is a schematic diagram of a reference curve graph provided in an embodiment of the present application, wherein the horizontal axis of the reference curve graph is the height distance, and the vertical axis is the image energy concentration value. Figure 7 It can be seen that when the height distance is X, the corresponding image energy concentration value is the highest, and the image energy concentration value is Y. Therefore, it means that when the height distance is X, the corresponding imaging quality is the highest. Therefore, the height distance X can be determined as the target height distance.

[0097] In some embodiments, after determining the target height distance based on the reference images of the reference object at multiple different height distances, the stage can also be controlled to move to a corresponding height in the vertical direction according to the target height distance, and the height value of the upper surface of the reference object when the stage is at this height is obtained as the target height value. The target height value is used to indicate the height value that the upper surface of the test area corresponding to the object to be tested needs to be at when it is in the initial scanning position.

[0098] That is to say, the upper surface of the object to be measured and the upper surface of the reference object may not be in the same horizontal plane because the bottom surfaces of the first bearing area and the second bearing area of ​​the stage are not in the same horizontal plane, or because the thickness of the object to be measured is different from the thickness of the reference object. Therefore, after determining the target height, it is also necessary to obtain the height value of the upper surface of the reference object when the stage is at this height as the target height value.

[0099] Therefore, in the subsequent process, the target height value can be determined as the height value that the upper surface of the test area corresponding to the object to be tested needs to be at when it is in the initial scanning position, thereby improving the imaging quality when detecting the test area in the object to be tested, and further improving the detection accuracy of the object to be tested.

[0100] In addition, in some embodiments, when the depth of field of the imaging system is greater than the range in which the optimal object distance may drift, or when the optimal object distance is not sensitive to environmental parameters such as temperature, it is possible to avoid focusing, i.e., focal plane calibration, and directly move the object to be tested to the nominal object plane for subsequent testing. In this way, there is no need to perform a focus-seeking process or introduce a reference object, thereby simplifying the process.

[0101] The embodiment of the present application introduces a reference object, and the reference object is located in the second bearing area of ​​the stage, and by controlling the relative movement of the stage and the objective lens in the vertical direction, and controlling the reference object on the stage to be photographed at each height distance, a plurality of reference images can be obtained, and then, the target height distance is determined according to the reference images of the reference object at a plurality of different height distances. That is, the embodiment of the present application is based on the reference object for focus search, thereby avoiding the situation that it is difficult to find a fixed graphic feature as the object of focus imaging due to the different graphic types corresponding to each area of ​​the object to be tested, and the accuracy of focus search can be improved, thereby improving the imaging quality of the object to be tested in the subsequent process, and then improving the detection accuracy of the object to be tested; and, when the object to be tested is directly focused, it can avoid the situation that errors are generated due to the fluctuations of the graphic structure of the object to be tested and the Talbot effect. In addition, the reference curve graph is determined according to the height distances corresponding to the multiple image energy concentration values ​​and the multiple reference images, thereby, in the subsequent process, the target height distance can be directly determined from the reference curve graph. Moreover, taking the average value of the energy concentration values ​​of multiple regions as the image energy concentration value corresponding to the reference image can improve the accuracy of the determined target height distance.

[0102] Figure 8 is a flowchart of another focus finding method provided in an embodiment of the present application, which is applied to the processor in the above detection device. Figure 8 , the method comprises the following steps: Step 801: Control the relative movement of the stage carrying the reference object and the objective lens in the vertical direction, so that the reference object carried on the stage and the objective lens are at a plurality of different height distances in the vertical direction in sequence.

[0103] In some embodiments, the stage has a first bearing area, and the first bearing area is used to bear the object to be measured; the reference object is the object to be measured. In other words, the focus can be directly searched according to the object to be measured. In this case, the stage can have only the first bearing area, and only the first bearing area needs to be used to bear the object to be measured, that is, the object to be measured can also be used as a reference object.

[0104] Step 802: At each height distance, control the reference object on the stage to be photographed to obtain a reference image of the reference object at each height distance.

[0105] Step 802 is the same as the above-mentioned step 202. Please refer to the relevant content of step 202, which will not be repeated here.

[0106] Step 803: Determine a target height distance based on reference images of the reference object at multiple different height distances. The target height distance is used to determine the initial height distance between the stage or the object to be measured and the objective lens when scanning the object to be measured when the object to be measured is carried on the stage.

[0107] In some embodiments, for each reference image among the multiple reference images: multiple focus regions in the reference image are determined, and then, regional energy concentration values ​​corresponding to the multiple focus regions are determined, and based on the multiple regional energy concentration values, an image energy concentration value corresponding to the reference image is determined, and then, based on the image energy concentration values ​​corresponding to the multiple reference images and the height distances corresponding to the multiple reference images, the target height distance is determined.

[0108] The detailed process of determining the target height distance has been described in detail in the above step 203, which will not be repeated here. Please refer to the above content.

[0109] The embodiment of the present application uses the object to be measured as a reference object without introducing additional reference objects. Focusing can be performed directly based on the object to be measured, and a more targeted focusing process can be performed on different objects to be measured. For different objects to be measured, accurate target height distances can be determined.

[0110] Fig. 9 is a flow chart of a semiconductor detection method provided by an embodiment of the present application, which is applied to the processor in the above detection device. Fig. 9 , the method comprises the following steps: Step 901: Control the relative movement of the stage and the objective lens carrying the object to be measured along the scanning direction to reach multiple scanning positions in sequence, wherein the object to be measured is a semiconductor sample; wherein the relative movement of the stage and the objective lens in the vertical direction is controlled according to a target height distance so that the upper surface of the test area corresponding to the object to be measured at the initial scanning position is at a desired height, and the target height distance is determined based on any embodiment of the above-mentioned focusing method.

[0111] That is to say, the target height distance can be determined by the focusing method in any of the above embodiments, and thus, control can be performed based on the determined target height distance so that the upper surface of the test area corresponding to the initial scanning position of the object to be tested is at the desired height, that is, at the target height value.

[0112] Step 902: During the scanning process, the upper surface of the test area corresponding to the object to be tested at the initial scanning position is at a desired height as the follow-focus zero point to control full follow-focusing of the object to be tested, and after automatic focusing at each scanning position, the object to be tested is controlled to be imaged to obtain a test image of the test area corresponding to the object to be tested at the current scanning position.

[0113] In some embodiments, the object to be tested corresponds to different areas to be tested at different scanning positions. By imaging the different areas to be tested of the object to be tested at a plurality of different scanning positions, scanning and imaging of the surface of the object to be tested can be completed.

[0114] Step 903: Detect the area to be tested based on the image to be tested.

[0115] For example, defect detection may be performed on the area to be tested based on the image to be tested.

[0116] It can be understood that step 903 can detect the corresponding area to be tested based on the image to be tested based on an existing or future detection algorithm.

[0117] The embodiment of the present application determines the target height distance through a reference image, and determines the expected height of the upper surface of the test area corresponding to the object to be tested at the initial scanning position based on the target height distance, so that the expected height is used as the focus zero point control to perform full follow-focus on the object to be tested, which can realize dynamic adjustment during the scanning process, ensure accurate and automatic following, and always maintain the best focal plane.

[0118] This document is described with reference to various exemplary embodiments. However, those skilled in the art will recognize that changes and modifications may be made to the exemplary embodiments without departing from the scope of this document. For example, various operating steps and components for performing the operating steps may be implemented in different ways (e.g., one or more steps may be deleted, modified, or combined into other steps) depending on the specific application or considering any number of cost functions associated with the operation of the system.

[0119] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. In addition, as understood by those skilled in the art, the principles of this article can be reflected in a computer program product on a computer-readable storage medium, which is pre-installed with a computer-readable program code. Any tangible, non-temporary computer-readable storage medium can be used, including magnetic storage devices (hard disks, floppy disks, etc.), optical storage devices (CD to ROM, DVD, Blue Ray disks, etc.), flash memory and / or the like. These computer program instructions can be loaded onto a general-purpose computer, a special-purpose computer, or other programmable data processing device to form a machine, so that these instructions executed on a computer or other programmable data processing device can generate a device that implements a specified function. These computer program instructions can also be stored in a computer-readable memory, which can instruct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory can form a manufactured product, including an implementation device that implements a specified function. Computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operating steps are performed on a computer or other programmable device to generate a computer-implemented process, so that the instructions executed on a computer or other programmable device can provide steps for implementing a specified function.

[0120] Although the principles of this invention have been shown in various embodiments, many modifications of structures, arrangements, proportions, elements, materials and components particularly suitable for specific environments and operational requirements can be used without departing from the principles and scope of this invention. The above modifications and other changes or amendments will be included in the scope of this invention.

[0121] The foregoing specific description has been described with reference to various embodiments. However, those skilled in the art will recognize that various modifications and changes can be made without departing from the scope of the present disclosure. Therefore, the consideration of the present disclosure will be illustrative rather than restrictive, and all these modifications will be included in its scope. Similarly, the advantages, other advantages and solutions to the problems of various embodiments have been described above. However, the benefits, advantages, solutions to the problems and any elements that can produce these, or make them more clear, should not be interpreted as critical, necessary or necessary. The term "include" and any other variants used in this article are all non-exclusive inclusions, so that the process, method, article or device including the list of elements not only includes these elements, but also includes other elements that are not explicitly listed or do not belong to the process, method, system, article or device. In addition, the term "coupled" and any other variants used in this article refer to physical connections, electrical connections, magnetic connections, optical connections, communication connections, functional connections and / or any other connections.

[0122] Those skilled in the art will appreciate that many changes may be made to the details of the above-described embodiments without departing from the basic principles of the invention. Therefore, the scope of the present invention should be determined solely by the claims.

Claims

1. A focus finding method, characterized in that: The method comprises: Controlling the relative movement of the stage carrying the reference object and the object to be measured and the objective lens in the vertical direction, so that the reference object carried on the stage and the objective lens are at a plurality of different height distances in the vertical direction in sequence; wherein the stage has a first carrying area and a second carrying area, the first carrying area is used to carry the object to be measured, and the second carrying area is used to carry the reference object; At each height distance, controlling the reference object on the stage to be photographed to obtain a reference image of the reference object at each height distance; Based on the reference images of the reference object at a plurality of different height distances, a target height distance is determined, and the target height distance is used to determine an initial height distance between the stage or the object to be measured and the objective lens when scanning the object to be measured.

2. The focus-finding method according to claim 1, wherein: After determining the target height distance based on the reference images of the reference object at a plurality of different height distances, the method further comprises: Control the stage to move to a corresponding height in the vertical direction according to the target height distance, and obtain the height value of the upper surface of the reference object when the stage is at this height as the target height value, and the target height value is used to indicate the height value that the upper surface of the test area corresponding to the object to be tested needs to be at when it is in the initial scanning position.

3. The focus-finding method according to claim 1, wherein: Determining the target height distance based on the reference images of the reference object at a plurality of different height distances comprises: For each reference image in the plurality of reference images: determining a plurality of focus regions in the reference image; determining regional energy concentration values ​​corresponding to the plurality of focus regions respectively; and determining an image energy concentration value corresponding to the reference image based on the plurality of regional energy concentration values; The target height distance is determined based on the image energy concentration values ​​respectively corresponding to the multiple reference images and the height distances respectively corresponding to the multiple reference images.

4. The focus-finding method according to claim 3, wherein: The determining, based on the plurality of regional energy concentration values, an image energy concentration value corresponding to the reference image comprises: An average value of the plurality of regional energy concentration values ​​is used as the image energy concentration value corresponding to the reference image.

5. The focus-finding method according to claim 3 or 4, characterized in that: The determining the target height distance based on the image energy concentration values ​​respectively corresponding to the plurality of reference images and the height distances respectively corresponding to the plurality of reference images comprises: Obtaining a reference curve graph according to the plurality of image energy concentration values ​​and the height distances respectively corresponding to the plurality of reference images; The height distance corresponding to the maximum image energy concentration value in the reference curve graph is determined as the target height distance.

6. The focus-finding method according to claim 3, wherein: The determining of the regional energy concentration values ​​respectively corresponding to the plurality of focus regions comprises: For each of the plurality of regions of interest: Determine a central pixel in the focus area, where the central pixel is a pixel with the largest grayscale value in the focus area; Taking the central pixel as the center, determining a first sub-region, a second sub-region and a third sub-region in the region of interest, wherein the first sub-region is located at the periphery of the central pixel, the second sub-region is located at the periphery of the first sub-region, and the third sub-region is other regions in the region of interest that are located at the periphery of the second sub-region; Based on the first sub-region, the second sub-region and the third sub-region, corresponding regional energy concentration values ​​are determined.

7. The focus-finding method according to claim 6, wherein: The determining of corresponding regional energy concentration values ​​based on the first sub-region, the second sub-region, and the third sub-region includes: determining an average noise based on pixels in the second sub-area and pixels in the third sub-area; Determine a plurality of grayscale pixels in the first sub-region, wherein the plurality of grayscale pixels include a first pixel in the first sub-region having a maximum grayscale value and at least one pixel whose grayscale value is successively smaller than the grayscale value of the first pixel; determining a first energy value based on the plurality of grayscale pixels and the average noise; determining a second energy value based on pixels in the second sub-region and the average noise; The regional energy concentration value is determined based on the first energy value and the second energy value.

8. The focus-finding method according to claim 7, wherein: The determining a first energy value based on the plurality of grayscale pixels and the average noise comprises: Deducting the average noise from each grayscale pixel of the plurality of grayscale pixels to obtain a plurality of grayscale pixels after deducting the average noise; The grayscale values ​​of the plurality of grayscale pixels after deducting the average noise are added together to obtain the first energy value.

9. The focus-finding method according to claim 7 or 8, characterized in that: The determining, based on the pixels in the second sub-region and the average noise, a second energy value comprises: Deducting the average noise from each pixel in the second sub-area to obtain a plurality of pixels after deducting the average noise; The grayscale values ​​of the plurality of pixels after deducting the average noise are added together to obtain the second energy value.

10. The focus-finding method according to claim 9, wherein: The determining the regional energy concentration value based on the first energy value and the second energy value comprises: The ratio of the first energy value to the second energy value is determined as the regional energy concentration value.

11. The focus-finding method according to claim 1, wherein: The reference object is a standard part, the surface of which has a plurality of circular pits with the same diameter and the same recessed distance, and the plurality of circular pits are arranged in a rectangular shape; or, The reference object is another object to be tested that is different from the object to be tested located in the first carrying area.

12. The focus-finding method according to claim 1, wherein: The bottom surfaces of the first bearing area and the second bearing area are in the same horizontal plane.

13. A focus finding method, characterized in that: The method comprises: Controlling the relative movement of the stage carrying the reference object and the objective lens in the vertical direction, so that the reference object carried on the stage and the objective lens are at a plurality of different height distances in the vertical direction in sequence; At each height distance, controlling the reference object on the stage to be photographed to obtain a reference image of the reference object at each height distance; Based on the reference images of the reference object at multiple different height distances, a target height distance is determined. The target height distance is used to determine the initial height distance between the stage or the object to be measured and the objective lens when scanning the object to be measured when the object to be measured is carried on the stage.

14. The focus-finding method according to claim 13, wherein: The stage has a first bearing area, and the first bearing area is used to bear the object to be measured; the reference object is the object to be measured.

15. The focus-finding method according to claim 13 or 14, characterized in that: Determining the target height distance based on the reference images of the reference object at a plurality of different height distances comprises: For each reference image in the plurality of reference images: determining a plurality of focus regions in the reference image; determining regional energy concentration values ​​corresponding to the plurality of focus regions respectively; and determining an image energy concentration value corresponding to the reference image based on the plurality of regional energy concentration values; The target height distance is determined based on the image energy concentration values ​​respectively corresponding to the multiple reference images and the height distances respectively corresponding to the multiple reference images.

16. A semiconductor detection method, characterized in that: The method comprises: Controlling the relative movement of a stage carrying an object to be tested and an objective lens along a scanning direction to sequentially reach a plurality of scanning positions, wherein the object to be tested is a semiconductor sample; wherein the relative movement of the stage and the objective lens in a vertical direction is controlled according to a target height distance so that the upper surface of the test area corresponding to the object to be tested at an initial scanning position is at a desired height, wherein the target height distance is determined based on the focusing method according to any one of claims 1 to 15; During the scanning process, the upper surface of the test area corresponding to the test object at the initial scanning position of the test object is at a desired height as the follow focus zero point to control the full follow focus of the test object, and after automatic focusing at each scanning position, control the imaging of the test object to obtain the test image of the test area corresponding to the current scanning position of the test object; The area to be tested is detected based on the image to be tested.

17. A detection device, characterized in that: include: The stage has a first carrying area, and the first carrying area is used to carry the object to be tested; Imaging optical path components, including detection sensors and objective lenses; The imaging optical path component is used to perform optical imaging of the object to be tested and the reference object on the stage through the objective lens, and transmit the optical signal obtained by imaging to the detection sensor, and the detection sensor is used to convert the optical signal into an electrical signal, so as to obtain a detection image of the object to be tested and / or a reference image of the reference object; A driving assembly, used for driving the stage and the objective lens to move relative to each other; A processor, configured to execute the method according to any one of claims 1 to 16.

18. The detection device according to claim 17, characterized in that The object carrier also has a second carrying area, and the second carrying area is used for carrying a reference object.

19. A computer-readable storage medium, characterized in that: A computer program is stored on the medium, and the computer program can be executed by a processor to implement the method according to any one of claims 1 to 16.

Images